This invention relates to enhancing safety at a site, such as a home or a commercial building, which obtains power from both (1) a photovoltaic (PV) power source, and (2) another power source, typically a utility power source.
Fire departments typically shut off the main disconnect at the electrical panel when responding to a fire to ensure that all electrical circuitry within a building is deactivated. However, PV panels, typically located on the roof of the building, are energized whenever light shines on them. Therefore, during daylight hours the DC PV circuitry from the PV panels to the inverter and any other control electronics, which may be run inside and/or outside the building, remains electrically energized even when the AC circuitry has been deenergized, such as when the main disconnect has been shut off. Therefore, fire departments often require an external disconnect switch adjacent to the PV panels, typically on the roof, to allow fire department personnel to deactivate all circuits in the building from any power supplied by PV panels.